The use of laparoscopic surgical procedures has increased dramatically in recent years. All of these procedures include the following basic steps: passing a small diameter cylindrical port through the abdominal wall, inflating the abdomen with a gas such as carbon dioxide, and passing surgical instruments through the port and into the abdomen. Optical fibers can be passed through the port and the surgical procedures can be monitored on a television screen. Surgical cutting and cauterizing can be performed with an electrosurgical instrument or a focused laser beam, typically from a CO.sub.2 laser. In laser laparoscopy the laser beam is transmitted in a laparoscopic port through the abdominal muscular wall of a patient into the abdominal cavity where the laser beam is used to excise or remove body tissue by vaporization. Laser laparoscopic surgical procedures are used to treat a number of gynecological problems including hydrosalpinx, endometriosis, small uterine fibroids, and pelvic adhesions. The only surgical opening required is a small incision though the abdominal wall because the laparoscopic port is small, typically about 12.7 mm in diameter. Use of this procedure avoids the risk of laparotomy requiring full size abdominal incisions.
With the rapid expansion in the use of a lasers as surgical instruments, new problems have been encountered which have not been confronted in conventional surgery. One such problem is that of the smoke or laser plume produced during laser surgery. While some smoke may be produced by conventional electric scalpels and similar devices, the intensity and volume of the smoke and pollutants produced in laser surgery presents a problem of a much larger magnitude.
The high intensity of lasers used in laser surgery causes oxidation of tissue and fluid contacted by the laser. This typically results in a dense laser plume emitted from the surgical site. The laser plume contains a variety of hydrocarbon compounds, carbon monoxide, moisture, and unpleasant odors. It is also now conjectured that the laser plume may contain quantities of biologically viable material, which could range in content from relatively benign organisms to cancerous and deadly viral materials.
In one study which sought to determine the scope and intensity of the smoke produced during surgery, tissue was contacted by a laser under controlled conditions. It was found that the smoke and particulate matter produced a density approximately 52 times greater than the recommended density set by the governmental regulatory agencies.
In addition, the laser plume is known to contain particles of varying sizes. For example, one investigation found particles varying in size from under 0.4 microns to over 9.0 microns. Nevertheless, a large portion of the particles found in that study were under 1.1 microns in size which are capable of being easily deposited in the alveoli of the lungs. Not only are particles of this size irritating to the respiratory system, but they may also be capable of causing serious respiratory disease. Repeated exposure to such particles can build deposits within the lungs.
Several investigators have pointed out that repeated exposure to laser plumes may result in pneumonitis. In addition, it has been found that the laser plume may be mutagenic, and thus possibly carcinogenic. The presence of biologically viable materials poses the risk of the spread of contagions. While much of the data in this area is still not definitive, it is clear that direct contact with laser plume presents significant health risks, particularly to exposed medical personnel and patients.
Laser plumes present additional difficulties. For example, it has been found that the laser plumes condense on the optical components of the laparoscope itself, thereby impairing visibility or causing pitting damage to lenses. Similarly, the laser plume may enter and clog mechanical devices and filters located in the operating room.
In order to combat the problems of damage to the laser itself, many conventional laser systems are equipped with air circulation systems. These systems drive a stream of air over the sensitive laser equipment and the area being contacted by the laser beam. While the laser plume is thus driven away from the laser equipment, it is forced into the ambient air, making it more difficult to control laser plume emissions.
Also, the superheated steam component of the laser plume may cause serious burns in the event of contact with flesh. Of course, the primary danger in this regard is to the patient. The steam is produced by vaporizing irrigation or body fluids, and there is a danger that those vaporized fluids may contact the surrounding tissue.
When the steam does leave the localized surgical site, there is a danger that the heat may cause discomfort or otherwise provide an undesirable distraction to the surgeon or other operating room personnel. Thus, it is controlled and removed from the surgical site before it injures the tissues surrounding the surgical site or becomes a problem to operating room personnel.
Good practice thus dictates that the laser plume be controlled and removed from the surgical site, and various devices have been developed for this purpose. Most involve the use of some form of suction.
The following patents outline the state of the art in laser smoke removal processes and vacuum line control systems.
U.S. Pat. No. 5,055,100 (Olsen) relates to a clip-on attachment for an electrosurgical instrument. A back end of the attachment, which includes a hollow tube, is adapted for connection to a source of low fluid pressure. A front end of the attachment is situated near the front end of the electrode for more efficient removal of smoke and other fluids.
U.S. Pat. No. 3,319,628 (Halligan) discloses a suction catheter regulator device formed of relatively rigid plastic material and having an integrally formed control tube extending transversely from a conduit tube. The control tube is provided with an outer open end with a flanged finger engaging piece surrounding the open end.
U.S. Pat. No. 3,982,541 (L'Esperance, Jr.) relates to an eye surgical instrument for performing laser surgery comprising a probe having a central tube disposed within an outer tube. The central tube is open at both ends with one end disposed within the probe and the other end exposed at a free end of the probe for contact with body tissue. A laser beam is directed through the central tube. A means is connected to the probe for removing smoke and vaporized portions of tissue through the space between the tubes in a direction away from the free end of the probe.
U.S. Pat. No. 5,047,072 (Wertz et al) discloses a portable system for evacuating laser smoke from a surgical site comprising a primary inlet tube supported on an articulated arm, a suction canister in communication with the primary inlet tube, a primary filter canister in connection with the suction canister by means of a secondary inlet tube, and a disposable prefilter disc. A fan, positioned downstream of the primary filter canister is employed for advancing laser smoke through the portable system.
U.S. Pat. No. 3,998,227 (Holbrook et al) discloses a regulator device for hospital vacuum systems comprising a base housing having an air outlet and means for providing a variable, atmospheric air inlet to the base house. The base housing has an air passageway means between air outlet and inlet of a transverse open cross-sectional area not greater than 0.002 square inches.
U.S. Pat. No. 4,735,603 (Goodson et al) discloses a laser smoke evacuation system for use with laser laparoscopic surgery. In a preferred embodiment, the CO.sub.2 gas employed to distend the abdominal area of the patient is withdrawn in incremental amounts, purified by removal of laser smoke and returned to the patient cavity. A bacterial filter is also employed to remove microorganisms. An entire closed circuit CO.sub.2 gas recirculation system is disclosed.
U.S. Pat. No. 3,834,388 (Sauer) discloses a suction control arrangement for a suction catheter, the control arrangement having an opening to the atmosphere which can be slidably opened or closed. When a slide is in the open position, the internal flow of the catheter is exposed to the atmosphere and the vacuum and suction force is eliminated thus preventing fluid flow out of any body cavities.